Method for carbon bisulfide production



July 12, 1955 K. w. GUEBERT METHOD FOR CARBON BISULFIDE PRODUCTION Filed May 28. 1951 IN VEN TOR. Kenne/ MZ 6065er/ ATTORNEYS United States Patent METHD FR CARBGN BISULFIDE PRODUCTIN Kenneth W. Guebert, Freeport, Tex., assignor to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Application May 2S, 1951, Serial No. 223,733

4 Claims. (C1. 23-206) This invention relates to a method for carbon bisulde production, and, more particularly, to a novel catalytic process for the manufacture thereof from sulfur and a paraffinic hydrocarbon.

it was known prior to the present invention that parainic hydrocarbons and sulfur, in liquid phase or in vapor phase, would react at elevated temperatures to produce carbon bisulde and hydrogen sulfide. it was also known that this reaction was catalyzed by certain agents, such as silica gel, fullers earth, bauxite, activated alumina, copper phosphate, zirconium phosphate. and thorium phosphate.

The present invention is based upon the discovery of a novel catalytic agent for the reaction between sulfur and a paratlnic hydrocarbon.

According to the invention carbon bisulde is produced by contacting a vapor phase mixture of sulfur and a paranic hydrocarbon with a high silica glass promoted by cobaltous oxide at a temperature from 500 to 700 C. righ silica glass is used herein to refer to glasses containing at least 90 per cent by weight of silica. Vycor glass, a commercial product containing from 90 to 96 per cent of silica, produced by extracting a substantial portion of the other components from high silica glass, is suitable high silica glass.

A high silica glass promoted with CoO is readily produced by impregnating particles of the desired glass of suitable size with an aqueous solution of cobaltous chloride, drying the impregnated particles, and heating them in an air stream at from 400 to 600 C. it is usually preferred that the glass be promoted with from l to per cent or" the oxide. T he terms per cent and parts" are used herein to refer to per cent and parts by weight, unless otherwise indicated.

The process of the invention may be more readily understood by reference to the accompanying drawing. which is a schematic flow sheet illustrating the produc1 tion of carbon bisuliide, using a cobalt oxide promoted Vycor glass catalyst.

Liquid sulfur from a liquid sulfur supply 11 tlows through a line 12 and into a line 13 Where it is mixed with natural gas from a natural gas supply 14 which cws through a line 15 into the line 13. The natural gas-sulfur mixture passes through the line 13 into a vaporizer 16, and from thence through a line 17 to a reactor 13 packed with the catalyst. Reaction products pass from the reactor through a line 19 to a sulfur condenser 20 where any unreacted sulfur is removed. Products remaining pass from the sulfur condenser through a line 21 to a cooled trap 22 where carbon bisuliide and some hydrogen sulde are condensed and collected. The remaining products, mainly H28, then ow through a line 23 to a scrubber 24 where hydrogen sulfide is absorbed by dilute aqueous sodium hydroxide that is passed into the scrubber through a line 25. Relatively dilute sodium suliide passes from the bottom of the scrubber through a line 26. A small amount of by-product leaves the scrubber through a line 27.

The method of the invention is suitable for the production of carbon bisuliide at temperatures ranging from 500 to 700 C. However, it is preferred to carry out the process at temperatures from 560 to 600 C., as

reaction proceeds at a practical rate within the above ternperature range, and corrosion of metallic reaction apparatus is minimized. The reaction proceeds satisfactorily at atmospheric pressure, although either reduced or elevated pressures can be used if desired.

It is practical to carry out the process of the invention using a space velocity from 200 to 1200. Space velocity is defined as the ratio of total volume of the gases, calculated at 0 C. and 760 mm. Hg total pressure, passed over the catalyst per hour divided by the apparent volume of the catalyst. Within the above range, the selection of a lower space velocity results in a higher yield, but a lower production rate per unit of reactor volume. Accordingly, the space velocity used in a given application is a compromise between these two factors. it is usually preferred that the space velocity be from 700 to 900.

in general, any available source ot' parafhnic hydrocarbon gases can be used in carrying out the process ot the invention. Natural gas provides a convenient supply, preferably a natural gas high in methane. Although it is feasible to carry out the reaction of the invention using a substantial excess either of sulfur or of the paraiiinic hydrocarbon, it is usually preferred to use from 90 to 110 per cent of the sulfur theoretically required to convert all the carbon in the paranic hydrocarbon to carbon bisulfide, and all the hydrogen therein to hydrogen sulfide.

Example Carbon bisulde was produced from a Texas natural gas containing about 90 per cent by volume of methane by passing a vapor mixture of sulfur and the natural gas, in a weight ratio of about l5 parts of natural gas per 100 parts of sulfur, over Vycor glass in the form of particles of from 8 to 14 mesh, U. S. Sieve Series, promoted with cobaltous oxide, at a space velocity of 890. The per cent conversion of natural gas charged to carbon bisulde was found to be a function of temperature, ranging from 47 per cent conversion at a reaction temperature of 540 C., to a 60 per cent conversion at a reaction temperature of 575 C., to a 70 per cent conversion at a reaction temperature of 595 C., and an per cent conversion at a reaction temperature of 620 C.

I claim:

1. A method of producing carbon bisulide that comprises contacting a vapor phase mixture of sulfur and a paraillnic hydrocarbon with a catalyst consisting of particles of an extracted high silica glass containing at least per cent by weight silica promoted by cobaltous oxide at a temperature from 500 to 700 C.

2. A method as claimed in claim 1 in which the temperature is from 560 to 600 C.

3. A method of producing carbon bisulide that cornprises contacting a vapor phase mixture of sulfur and methane with a catalyst consisting of particles of an extracted high silica glass containing from 90 to 96 per cent by weight of silica promoted with from l to 10 per cent of cobaltous oxide at a temperature of 560 to 600 C.

4. A method as claimed in claim 3 in which the space velocity is from 200 to 1200.

References Cited in the file of this patent UNTED STATES PATENTS 2,079,543 Bley May 4, 1937 2,106,744 Hood et a1 Feb. 1, 1938 2,187,393 De Simo Jan. 16, 1940 2,330,934 Thacker Oct. 5, 1943 2,369,377 Thacker Dec. 13, 1945 2,428,727 Thacker Oct. 7, 1947 2,565,215 Follrins et al. Aug. 21, 1951 

1. A METHOD OF PRODUCING CARBON BISULFIDE THAT COMPRISES CONTACTING A VAPOR PHASE MIXTURE OF SULFUR AND A PARAFFINIC HYDROCARBON WITH A CATALYST CONSISTING OF PARTICLES OF AN EXTRACTED HIGH SILICA GLASS CONTAINING AT LEAST 90 PER CENT BY WEIGHT SILICA PROMOTED BY COBALTOUS OXIDE AT A TEMPERATURE FROM 500* TO 700* C. 